New observations and models of the middle corona have begun to bring this region and its unique properties into sharper focus. The region – which encompasses the transition from the predominantly closed magnetic field of the inner corona to the open, radial field of the outer corona – hosts complex topological interfaces that strongly influence outgoing coronal mass ejections (CMEs), shocks, and solar wind flow, while giving rise to inflows that can disturb and destabilize structures much lower in the atmosphere. 

Characterizing its emission, as well as the relationships between emission, temperature, density structure, and energetics, requires new observational methods and models to capture and interpret data. In this session we welcome contributions that highlight both new and planned observations, modeling approaches, or analysis projects that address many key questions about the middle corona, its properties, and its role in modulating the interface between Sun and Heliosphere.